The Islamic State of Iraq and Syria’s effort to inspire troubled Americans to violence has become more of a terror threat to the U.S. than an external attack by al Qaeda, the FBI director said Wednesday.

FBI Director James Comey said Thursday that U.S. authorities were able to thwart attacks tied to the July Fourth holiday, arresting multiple individuals who were plotting to do something on the national holiday.

A former CIA official wouldn’t be surprised if there’s a terror attack against the United States over the Fourth of July weekend after the FBI and the Homeland Security Department issued a bulletin of potential attacks against law enforcement officers and the military over the holiday.

A gunman rushed from the beach into a hotel in the Tunisian resort town of Sousse Friday, killing at least 28 people and wounding dozens more in the latest attack on the North African country’s key tourism industry, the Interior Ministry said.